The handling for FPSIMD/SVE traps is multi stage and involves some trap manipulation which isn't quite so immediately obvious as might be desired so add a few more comments.
Signed-off-by: Mark Brown <[email protected]> --- arch/arm64/kvm/hyp/include/hyp/switch.h | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h index 58e14f8ead23..1995808d8766 100644 --- a/arch/arm64/kvm/hyp/include/hyp/switch.h +++ b/arch/arm64/kvm/hyp/include/hyp/switch.h @@ -173,6 +173,8 @@ static bool kvm_hyp_handle_fpsimd(struct kvm_vcpu *vcpu, u64 *exit_code) return false; /* Valid trap. Switch the context: */ + + /* First disable enough traps to allow us to update the registers */ if (has_vhe()) { reg = CPACR_EL1_FPEN; if (sve_guest) @@ -188,11 +190,13 @@ static bool kvm_hyp_handle_fpsimd(struct kvm_vcpu *vcpu, u64 *exit_code) } isb(); + /* Write out the host state if it's in the registers */ if (vcpu->arch.flags & KVM_ARM64_FP_HOST) { __fpsimd_save_state(vcpu->arch.host_fpsimd_state); vcpu->arch.flags &= ~KVM_ARM64_FP_HOST; } + /* Restore the guest state */ if (sve_guest) __hyp_sve_restore_guest(vcpu); else -- 2.30.2 _______________________________________________ kvmarm mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
